R E P O R T
FEBRUARY 2005
WOOD FINISHES AND STAINS
The overall market for wood finishes -- coatings which, unlike paint,
do not completely mask the wood’s appearance -- has been growing, along with the demand for environmentally preferable wood
finishes.
 The demand for finishes for wood furniture, floors, and fixtures
has increased from 82 million gallons to 100 million gallons over
the last 5 years.
 About $2 billion in wood finishes were sold in 2004.
G R E E N
S E A L ’ S
T
his increased demand
toxicity in household and building
for wood coatings has
products, manufacturers of wood
been driven by favorable
coatings are offering many more
housing markets fueled
products that are low in
by low interest rates, the
volatile organic compounds
trend toward larger, more
(VOCs) and formulated
expensive homes, and an
without aromatic solvents,
increase in homeowners
heavy metals, or cancerimproving and redecorating
causing chemicals. These
their dwellings, inside and
products are healthier for
out. At the same time,
the users of these products
decorating trends that focus
– namely, workers on new
on the warmth and beauty of
home construction projects and
wood in the form of exposed wood
do-it-yourself homeowners – as
floors, walls, and home
well as the occupants of
Wood-finish manufurniture increase the
buildings where these
demand for wood finishes facturers have also finishing products have
as alternatives to paint.
been applied. Woodstepped up the profinish manufacturers
duction of “green”
Many of the products
have also stepped up the
used to coat wood
products because of production of “green”
around the home have
products because of the
the rising interest
traditionally contained
rising interest among
among developers
volatile organic solvents
developers in obtaining
and other toxic chemicals in obtaining Leader- Leadership in Energy and
that have been linked to
Environmental Design
ship in Energy and
poor indoor air quality
(LEED) certification for
Environmental
and possible health
new buildings. Sales
impacts. But because
of waterborne coatings
Design (LEED)
of increasing public
(including paints and
certification for new
awareness of indoor air
wood finishes) now
buildings.
pollution and chemical
dominate the national
What is a
Wood Finish?
A finish is a liquid, paste, or
gel that can be spread thinly onto
wood. There are two basic types
of wood finish: those that form a
film or coating on the wood and
those that penetrate the wood
surface. Film finishes, which cure
hard and can be built up in layers,
include varnish, shellac, lacquer,
water- and latex-based semitransparent stains, and solid-color
stains. Penetrating finishes are
oil-based and don’t cure to a hard
film. These include oil finishes,
such as tung and linseed oil, and
oil-based stains.
market; in California, waterborne
coatings accounted for 83% of
sales of architectural coatings in
2001.
This Choose Green Report
focuses on interior and exterior
wood finishes used as architectural
The Choose Green Report is published
for Green Seal Environmental Partners.
To become an Environmental Partner,
or to receive a copy of this report,
contact Green Seal at (202) 872-6400
or greenseal@greenseal.org.
Green Seal President and CEO,
Arthur B. Weissman, Ph.D.
Researchers and Writers, Kimberly Davis,
P.E., Kristen VanHooreweghe and Mary
Swanson, The University of Tennessee,
Knoxville, Energy, Environment and
Resources Center
Design, Cutting Edge Design
Original printed on Green Seal-certified
Mohawk Satin Cool White Recycled
paper, 30% postconsumer content
This Choose Green Report was produced with assistance from the U.S.
Environmental Protection Agency’s
Pollution Prevention Division.
Copyright © 2005, Green Seal, Inc.
www.greenseal.org
GREEN SEAL
ENVIRONMENTAL PARTNER
2
Choose Green Report
coatings (excluding paint). The
report begins with a general
description of wood finishes
and continues with a discussion
of health and environmental
concerns associated with the
use of these finishes. The report
concludes with a description
of Green Seal’s criteria for
environmentally preferable wood
finishes and a list of product
recommendations.
A WOOD FINISH:
Protects wood from
scratches, dirt, and wear
Enhances wood’s natural
beauty, color, figure patterns, grain, and depth.
Preserves wood from water, oxidation, and the
sun’s ultraviolet rays.
Changes wood’s appearance by adding color and
hiding defects.
Wood finishes, rather than
paints, are often used to showcase
the natural beauty of wood grain,
such as on floors and interior trim.
Outside, wood finishes are used on
decks and siding.
Wood finishes can include a
number of components:
• Pigments or dyes are used in
wood stains to add color and
hide flaws.
• Resin is the natural or synthetic
film-forming component of
these finishes. (Resins are also
called binders, especially when
used in stains or paints, because
they hold – or bind – the
pigment to the wood surface.)
Resins include acrylics, vinyls,
alkyds, cellulosics, epoxies,
polyurethanes, and oils. The
type of resin determines the
finish’s hardness, flexibility, and
resistance to stains, solvents,
and water.
• Solvents and/or thinners are
used to maintain the finish
in liquid form. Solvents are
needed to dissolve resins.
Thinners are used to reduce
viscosity (thickness) of the
liquid. Some finishes contain
both solvents and thinners.
Solvent-based coatings typically
use organic solvents such as
alcohols, ketones, glycol ethers,
petroleum distillates (mineral
spirits, toluene, xylenes, and
naphtha), and turpentine. The
solvent in a waterborne coating
is usually a glycol ether, and
water is used as a thinner.
• Various additives
are used, in smaller
amounts, to adjust
drying time, prevent
fungus and mildew
growth, act as
thickeners, etc.
Varnishes. Technically, all resin-
and-solvent mixes are varnishes.
Shellac is a spirit varnish—it
uses distilled spirits (denatured
alcohol) as a solvent, while
spar varnish uses a drying-type
vegetable oil (typically tung
oil) combined with phenolic
resin. In today’s common
usage, “varnish” means a mix
of drying oil and a natural or
artificial resin that is
Beginning in the
cooked (often with an
inert-metal catalyst) to
1970s, increased
make a clear finish that
concerns over the
is typically used indoors.
impact of certain
Varnish, which cures
by chemical reaction
chemicals on hu(polymerization),
man health and
is known for good
the environment
resistance to heat,
solvents, and water.
accelerated a trend
Alkyd and polyurethane
toward the developvarnishes, however,
ment of high-solids
may contain high VOCs.
Water-based varnishes
(lower-VOC) finishes
using polyurethane or
and water-based
acrylic polymers have
products.
been developed that emit
lower VOCs.
For centuries, varnish
(a catch-all term for
clear wood finishes)
was made from resins
collected from natural
products such as tree
saps or insect secretions
and mixed with linseed
or other natural oils.
To create the final
product, the mixture was thinned
with turpentine. More recently,
synthetic resins derived from
coal tar and petroleum began to
replace the natural resins, and
petroleum distillates became the
most commonly used solvents.
The petroleum-based products
in the synthetic resins helped
increase durability. But, beginning
in the 1970s, increased concerns
over the impact of certain
chemicals on human health and
the environment accelerated a
trend toward the development of
high-solids (lower-VOC) finishes
and water-based products. A
resurgence in the use of pure oils
and shellacs containing natural
ingredients marks another recent
trend in wood finishes.
This Choose Green Report covers
varnishes, shellacs, lacquers,
natural oils, water-based wood
finishes, and wood stains.
Shellacs. In its pure form, shellac
is a natural resin secreted by
the lac insect, found mostly in
India and Thailand. Shellac
cures as its solvent, alcohol,
evaporates. Although it creates
a brilliant shine, shellac’s
uses are limited because of its
susceptibility to damage from
liquids and heat. Shellac is
useful for touch-ups because
it bonds well to most other
finishes. Shellac is also used
as a sealer and under-coat
with lacquer or varnish and
polyurethane. It may not be
compatible as a sealer under
certain polyurethanes, though,
because of the natural wax it
contains.
Lacquers. Lacquer is a clear finish
best suited for accenting wood
grain. It dries fast and is very
durable. The most common
type, nitrocellulose lacquer,
uses a binder made from a
natural polymer, cellulose,
which is derived from wood or
cotton. Lacquer thinner is a
blend of solvents, which may
include ketones and esters,
alcohols, and fast-evaporating
hydrocarbons such as toluene
or xylene. Like shellac, lacquer
cures by evaporation. Without
a clear protective coating,
it is easily scratched and
susceptible to water damage.
Another drawback to lacquer
is its typically high solvent
content.
Natural oils. Linseed and tung
oils are penetrating finishes
that cure by absorbing oxygen
from the air, a process that
strengthens the finish. Linseed
oil is extracted from flax seeds.
Boiled linseed oil used in wood
finishing has been mixed with
chemical additives to hasten the
drying time. Tung oil is derived
from the nuts of trees that
are native to Asia. These oils
are durable, water-resistant,
and easy to apply but require
several coats and are slowdrying. Natural oils that have
been heat-treated to increase
gloss and hardness and
reduce curing time are called
polymerized oils.
Water-based. Water-based
finishes are actually made up of
droplets of solvent-based finish,
usually acrylic or polyurethane,
and a solvent, usually a glycol
ether, with water functioning
as a thinner. Water-based
finishes cure by coalescing: the
droplets of finish move closer
together and interlock as the
water evaporates. Water-based
finishes offer minimal solvent
fumes, easy cleanup, and good
scuff resistance, but they may
raise the wood grain and offer
only moderate resistance to
water, heat, and solvents.
Wood Stains
A wood stain is a finish for
wood that contains a dye or
pigment. Stains typically impart
a semi-transparent or opaque
coating and are designed to
change the color of a surface
without concealing the grain
pattern or surface
Unlike paints,
texture. More and
more homeowners,
which form
builders, and
a film on the
architects are
surface, these
turning to
penetrating stains
stains soak into
instead of paints,
the wood, acespecially for
centing the wood
exterior use. Unlike
paints, which form a
grain rather
film on the surface,
than hiding it.
these stains soak into
the wood, accenting
the wood grain rather than hiding
it. Stains become part of the
wood, which helps to prevent the
cracking, peeling, chipping, or
blistering that commonly occurs
with paints.
Exterior stains. Exterior stains are
used primarily on wood siding,
shingles, decks and outdoor
structures, and furniture. They
are available in latex- and
oil-based formulas. Oil-based
semi-transparent stains offer
the best protection of wood
fully exposed to weather; they
can also be used on new or
weathered wood, or wood
previously finished with other
penetrating finishes, without
extensive surface preparation.
If a solid color is desired, latex
opaque stains are preferable
over oil-based opaque stains,
since they are more flexible,
have better color retention,
and are less prone to mildew.
However, extensive surface
preparation is required for
proper adhesion, and latex
stains in general should not be
used on structures exposed to
direct sunlight.
Interior stains. Interior
stains, used for
furniture and
woodwork, come in
either pigmented
or dye categories.
Both can have an oil,
synthetic, or water
base. Pigmented
stains color the wood
with the same type
of pigments used in
paint. They range in
color from almost clear
to semi-transparent.
They are easily applied
with a brush or a rag,
and are then wiped off
to control the depth
of the stain. An oil
or polyurethane finish
is often mixed with
the stain, so the
do-it-yourselfer can
complete the staining
and finishing job in one
step.
The American Lung
Association reports
that VOCs and their
byproducts can
produce a number
of physical problems, including eye
and skin irritation,
lung and breathing problems,
headaches, nausea,
muscle weakness,
and liver and
kidney damage.
Health and Environmental Concerns
As organic materials in finishes
evaporate during the drying/curing
process, VOCs are released into
the air, affecting indoor and
outdoor air quality. The American
Lung Association reports that
VOCs and their byproducts can
produce a number of physical
problems, including eye and skin
irritation, lung and breathing
problems, headaches, nausea,
muscle weakness, and liver and
kidney damage. VOC levels can
be ten times higher indoors than
outdoors, with numbers
rising up to 1,000 times
higher immediately
following application
of a new coat of finish.
Outside, VOCs released
into the atmosphere
can combine with
each other, or with
other substances in
the air, to create new
chemical compounds,
such as ground-level
ozone. Ozone is a
major component of
smog, which causes
negative health and
environmental impacts
when present in high
concentrations at
ground level.
VOCs are
considered air
pollutants, and
the amount that
can be released for
a given amount of
solids is now regulated
in many areas. Regulations that
restrict the amount of VOCs in
architectural coatings have been
enacted federally and in many
states, including California, New
York, Texas, Massachusetts,
New Jersey, and Arizona, with
legislation pending in many other
states. Legislation controlling
VOC content varies around the
country, but most U.S. companies
are formulating their finishes to
comply with California regulations,
which allow up to 350 grams per
liter (g/L) of VOCs in varnishes and
up to 250 g/L of VOCs in stains.
The Environmental Protection Agency’s National Volatile Organic
Compound Emission Standards for Architectural Coatings went into
effect in 1999, under the Clean Air Act.
The EPA determined that architectural coatings account for
9 percent of the VOC emissions from all products.
Other new air-quality regulations
for VOC levels are poised to go
into effect around the country,
some beginning in January 2005.
In many U.S. states, including
Delaware, District of Columbia,
Maryland, New Jersey, New York,
Pennsylvania, and Virginia, the
VOC limit for finishes will drop to
350 VOC g/L.
Wood finishes may also
contain other toxic ingredients.
For example, 1,4-dioxane and
acetaldehyde are suspected
carcinogens. N-methyl
pyrrolidinone is a reproductive
toxin. And aromatic solvents such
as toluene and xylene can cause
a number of health problems if
inhaled. All of these examples are
currently reported as ingredients
in some wood-finishing products.
Lead, a well-known toxic metal,
had been used as a metallic drier
in oil and resin varnishes; lead
has since been replaced by other
metals such as cobalt and zinc.
Metals may still be problematic
because of their environmental
toxicity and persistence.
Phthalates, used as plasticizers,
are of concern because they may
potentially affect human and
animal hormone systems. Ozonedepleting compounds, such as the
solvent 1,1,1-trichloroethane, have
been phased out of most products.
Wood finishes that include a
preservative, such as a fungicide,
must be registered under the
Federal Insecticide, Fungicide, and
Rodenticide Act.
Lower-VOC Finishes
Over the past few years,
regulation under the Clean Air
Act and consumer demand for
low-VOC finishes have led to
the creation of a variety of new
products. Many penetrating
finishes, such as semi-transparent
stains, have low solids content
(pigment, oils, polymers) and are
being reformulated to meet lowVOC regulations. To meet the VOC
requirements, these reformulated
finishes may contain higher
solids content, reactive diluents,
new types of solvents and/or cosolvents, or other non-traditional
substituents. These low-VOC
requirements favor film-forming
formulations over products that
penetrate the wood surface, since
traditional wood stains were
formulated to penetrate the wood,
and the new formulations that
meet the VOC requirements may
not penetrate as well.
Water-based Finishes
Another way to decrease air
emissions from wood finishes is to
change the formulation to a
water-based coating. The new
water-based products achieve
a dramatic improvement over
solvent-based finishes in terms
of VOC emissions and worker
comfort and health. Companies
that have successfully switched to
water-based
The new watercoatings
based products
have worked
closely
achieve a dramatic
with their
improvement over
suppliers to
solvent-based
determine
the best
finishes in terms of
water-based
VOC emissions and
formula for
worker comfort and
their specific
uses.
health.
Product
Recommendations
In order to recommend specific
wood-finish products, Green Seal
developed product selection criteria
and evaluated wood-finish products
currently available on the market.
These criteria are based on health
and environmental concerns
related to the use of wood finishes,
a review of existing environmental
standards and criteria for paints,
stains, and varnishes as well
as applicable state and federal
VOC regulations, and a survey of
product manufacturers. Existing
environmental standards and
criteria generally limit VOCs and
prohibit or limit carcinogens,
aromatic solvents, phthalates,
heavy metals, reproductive toxins,
and ozone-depleting chemicals.
We also surveyed wood-finish
manufacturers. Survey responses
and product data, such as Material
Safety Data Sheets (MSDSs), from
the companies that participated
in the Green Seal survey indicated
a number of products available
on the U.S. market that met our
selection criteria.
Stains generally contain less
VOCs, so the VOC limit is lower
for stains than for other finishes.
Other than VOC level, the selection
criteria were the same and are
indicated at the beginning of the
tables below. The first table lists
recommended interior and exterior
wood-finish products (excluding
stains). The second table lists
recommended interior and exterior
wood-stain products. The last
table provides contact information
for manufacturers with listed
products.
• Always review the manufacturer's recommendations before
applying any type of wood finish.
• Use proper respirators, ventilation, and protective clothing as
recommended by the finish manufacturer.
Choose Green Report
5
Table 1. Recommended Wood Coatings (Excluding Stains)
All of the recommended protective coatings listed in this table do not contain…
VOCs exceeding 350 g/L
Carcinogens
Aromatic solvents
Phthalates
Heavy metals and their compounds
Reproductive toxins
Ozone-depleting chemicals
Manufacturer
Product Names
AFM
AFM Naturals Clear Penetrating Oil
200
AFM Naturals Oil Wax Finish
200
Safecoat Polyureseal BP Satin
258
Safecoat Acrylacq Satin
273
Safecoat Acrylacq (5101)
281
Safecoat Acrylacq Gloss
283
BonaKemi Bona Eon 70
70
Bona Kemi
BonaKemi Bonaseal
Fuhr International
Fuhr Double Z Self Cross Linking Acrylic Clear Coat
200
0
Fuhr Ultra Clear Water base Lacquer
58
Fuhr Waterborne Urethane Finish
57
Hood Finishing Products
Hydrocote Resisthane Plus
27
Masters Blend
Masters Blend Tung Oil or China Wood Oil
Target Coatings
Target Coatings 9000 Series Super Clear Polyurethane
200
Target Coatings UltraSeal Water-Based Shellac
200
Target Coatings Oxford Ultima Spray Lacquer - 1000
250
Tried and True Wood Finishes
Van Technologies
Choose Green Report
0
Tried and True Danish Oil Finish
0
Tried and True Original Wood Finish
0
Tried and True Varnish Oil
0
VanUltra-545 UV Wood Sealer
2
VanUltra-540 UV Wood Sealer
7
VanAqua-240 WATER BASED WOOD SEALER
6
VOC concentration (g/L)
118
© 2005, Green Seal, Inc. Use of this table for commercial purposes is prohibited. Information in this table was confirmed with the manufacturer. It has not been independently verified by Green Seal unless otherwise identified as
Green Seal certified.
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All of the recommended stains listed in this table do not contain…
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VOCs exceeding 250 g/L
Carcinogens
Aromatic solvents
Phthalates
Heavy metals and their compounds
Reproductive toxins
Ozone-depleting chemicals
Manufacturer
Product Names
AFM
Safecoat DuroStain Clear Base
Bioshield
Bioshield Aqua Resin Stain Finish #33
Fuhr International
Fuhr Heritage Wiping Stains
VOC concentration (g/L)
208
0
80
Fuhr ZVOC® Exterior Deck Stain
0
Fuhr ZVOC® Exterior Waterbased Stain
0
Fuhr ZVOC® Universal Stain
0
Hood Finishing Products
Hydrocote Penetrating Stain
Van Technologies
VanUltra - 520 UV Curable Chestnut Stain
7
Van Aqua - 220 Water Based Wood Stain
49
Note for stains: recommended product lines can contain several different stain colors.
238
© 2005, Green Seal, Inc. Use of this table for commercial purposes is prohibited. Information in this table was confirmed with the manufacturer. It has not been independently verified by Green Seal unless otherwise identified as
Green Seal certified.
Table 2. Recommended Stains
Choose Green Report
7
NON-PROFIT ORG.
US POSTAGE
PAID
WASHINGTON, DC
PERMIT NO. 5515
1001 CONNECTICUT AVE., NW
SUITE 827
WASHINGTON, D.C. 20036
IN THIS ISSUE
— Recommended
Wood Coating and
Staining Products
— Wood finish components
— Lower VOC finishes
— Water-based finishes
MANUFACTURER CONTACT INFORMATION
AFM
800-239-0321
www.afmsafecoat.com
Bioshield
800-621-2591
www.bioshieldpaint.com
Bona Kemi
800-872-5515
www.bonakemi.com
Fuhr International
800-558-7437
www.fuhrinternational.com
Hood Finishing Products
800-229-0934
www.hoodfinishing.com
Masters Blend
860-651-5536
Not available
Target Coatings
800-752-9922
www.targetcoatings.com
Tried and True Wood Finishes
607-387-9280
www.triedandtruewoodfinish.com
Van Technologies
218-525-9424
www.vtcoatings.com